By Tom Z. Collina
As the House Armed Services Committee marks up its version of the fiscal 2013 defense authorization bill, some strange proposals are emerging. Perhaps the oddest, from Rep. Michael Turner (R-Ohio), chair of the strategic forces subcommittee, is to build another ground-based missile defense (GMD) site on the east coast by 2015.
But wait. The United States already has two GMD sites on the west coast, with 30 interceptors deployed in California and Alaska, to handle an attack from North Korea. And the Obama administration is building another interceptor system in Europe, known as the Phased Adaptive Approach (PAA), to handle attacks from Iran. Never mind that neither country has yet deployed long-range missiles that could reach the United States.
Even on the surface, it is clear that missile defense is a hard job. The GMD system has not had a successful intercept test since 2008, with two failures in 2010, and the PAA's Standard Missile-3 (SM-3) IB failed its first flight test in 2011.
But dig a little deeper and you'll find that neither system has been proven effective against a realistic target including decoys.
This is a big deal, because one of the most significant challenges to a successful intercept of a target warhead in outer space, known as midcourse intercept, is that the attacker can add numerous decoys or countermeasures to confuse and overwhelm the defense. If the defense cannot distinguish a real warhead from a fake, then it must shoot interceptors at all of them. Interceptor missiles would be in limited supply and are much more expensive to produce than decoys. Both the GMD and the SM-3 system are designed to intercept targets in space.
The Defense Science Board, an advisory group to the Pentagon, addressed this issue in a little-noticed September 2011 report, saying that "the importance of achieving reliable midcourse discrimination cannot be overemphasized." Missile defense is "predicated on the ability to discriminate" real warheads from other targets, "such as rocket bodies, miscellaneous hardware, and intentional countermeasures," the report said.
One way to pre-empt this challenge is for the defense to try to intercept a target missile before it has released its warhead and decoys. Intercepting missiles in their boost phase, while the rocket booster is still firing, is "currently not feasible," according to the report. Instead, the report considers "early intercept," defined as the interval between boost and warhead release. That phase, according to the report, lasts about 100 seconds.
The report concludes that early intercept, a mission that has been proposed for the missile interceptor system in Europe, "requires Herculean effort and is not realistically achievable, even under the most optimistic set of deployment, sensor capability, and missile technology assumptions." The main problem is that defensive missiles would not be able to reach the target quickly enough. "[I]n most cases 100 seconds is too late" to prevent the release of decoys, the report found, and "intercepts would have to be achieved well inside this timeline."
'Shooting at Missile Junk'
The Defense Science Board report goes on to say, "If the defense should find itself in a situation where it is shooting at missile junk or decoys, the impact on the regional interceptor inventory would be dramatic and devastating!" If the defense cannot prevent the release of decoys, it must be able to distinguish real targets from fakes. However, according to the report, "discrimination in the exo-atmosphere [i.e., space] is still not a completely solved problem."
This is a vast understatement. J. Michael Gilmore, the Pentagon's director of operational testing, testified before the House Armed Services Strategic Forces Subcommittee on March 6 that "comprehensive quantitative assessments" of U.S. missile interceptor systems "is still a number of years away."
Gilmore testified before the same subcommittee last year that MDA tried to conduct a test against decoys in December 2008, called FTG-05. "Although simple countermeasures were planned for FTG-05," he said, "a malfunction prevented deployment." The next two tests, FTG-06 and FTG-06a, successfully deployed simple countermeasures; but the "kill vehicles malfunctioned before they could complete their intercepts in the countermeasures environments," he said.
Missile defense on the east coast? Let's see if we can tackle the decoy problem first.